DE 101 23 790 has disclosed a camper with a roof part which can be moved hydraulically upwards. Moveable arm structures are arranged between the body and the roof part on the left-hand side and the right-hand side. Furthermore, a left-hand hydraulic cylinder and a right-hand hydraulic cylinder are provided, these cylinders each acting on an arm structure in order to move the roof part up and down. The raiseable roof part serves in particular to provide additional space in the camper.
The cylinders each have an opening connection and a closing connection, which are respectively in communication with the opening chamber and the closing chamber of the corresponding cylinder, so that when pressurized hydraulic fluid is simultaneously fed to the opening connections of the first and second hydraulic actuators the roof part moves towards the opening position, and when pressurized hydraulic fluid is simultaneously fed to the closing connections the roof part moves towards the closed position.
In particular in the case of campers, the roof part is sometimes moved while there is a load resting on it, for example a surfboard, ski box, etc. This load, in particular if the load is acting eccentrically on the roof part, in the case of the known vehicle gives rise to uneven movements of the roof part on the left-hand and right-hand sides, which in turn leads to undesirable mechanical loads on the arm structures.